1. Field of the Invention
The present invention relates to a cell controller for controlling a plurality of manufacturing machines constituting a manufacturing cell.
2. Description of the Related Art
In manufacturing factories, manufacturing machines, for example, machine tools or robots perform operations, such as, processing or welding of parts. In order to manufacture products, a plurality of manufacturing machines constitutes a manufacturing line, for example, a manufacturing cell. In this instance, the manufacturing machines constituting the manufacturing cell are controlled by a cell controller via a network communication. The cell controller drives each manufacturing machine based on commands from a production management device as a host computer.
In such a manufacturing cell, an abnormality occurs in a manufacturing machine, such as a robot, and thus, the manufacturing machine does not operate normally in some cases. Thus, the productivity reduces. In order to solve such a problem, various methods for early detection of abnormalities in manufacturing machines have been proposed.
For example, Japanese Patent Application Laid-open No. 2004-202624 discloses a device for collecting information from a plurality of robots connected via a network. Such a device predicts a robot which may break down, when a predetermined robot breaks down, by comparing the previously registered information on the robots with the real-time individual information on the robots. Japanese Patent Application Laid-open No. 2004-202624 also discloses that, based on the information on the robot predicted to break down, candidate parts necessary when the robot breaks down are extracted.
Japanese Patent No. 4739556 discloses an abnormality determining device having a simulator which uses a model identical to an actual robot, to reproduce the operation and state of the actual robot. This device compares the operation and state of the actual robot in response to an operation command with results of the reproduction made by the simulator, thereby determining whether an abnormality occurs in the operation and state of the actual robot.
In order to improve productivity, in general, when an abnormality occurs in a manufacturing machine, a cause of the abnormality should be early determined to quickly recover the manufacturing machine.
However, when the abnormality is caused by, for example, an improper setting or improper operation, it takes a lot of time to determine the cause of the abnormality.
In other words, the abnormality caused by an improper setting or improper operation can often be found by comparing the information obtained from a manufacturing machine that operates normally with the information obtained from a manufacturing machine in which the abnormality occurs. However, under present circumstances, a maintenance manager or a support engineer in a machinery manufacture needs to perform a series of operations including picking up the inside information of each manufacturing machine and comparing pieces of the inside information with each other, and accordingly, it takes a lot of time to determine the cause of the abnormality.
Thus, a technology for early detection of an abnormality which may be caused by the inside information of a manufacturing machine, such as an improper setting or an improper operation as described above, has been desired.
Note that, the device disclosed in Japanese Patent Application Laid-open No. 2004-202624 predicts a failure in a component of a manufacturing machine, such as a robot, but cannot predict the occurrence of an abnormality caused by an improper setting or an improper operation in a manufacturing machine, i.e., the inside information of the manufacturing machine. The same is true in the device disclosed in Japanese Patent No. 4739556. Further, in the device disclosed in Japanese Patent No. 4739556, if simulation errors occur when the simulator reproduces the operation and state of the actual robot in response to an operation command, the correctness of the results of abnormality determination reduces.